Writing is a super long process. If you're a writer - I mean if you're really a writer who has written and revised and rewritten and re-revised - then you know what I mean. When you finally get it to the point where you're happy with what you've written, you are eager to send it out into the world. I get that.
But the thing is, you are sending your ms out to an editor. And guess what that editor is going to do with your manuscript, even if she thinks it's the most brilliant thing ever written? Yup. She's going to edit it.
So with that in mind, here is a small piece of advice. Never EVER call your document something like MyManuscript_FINAL.doc. If you've ever done this, you need to go outside, turn around three times and spit in order to appease the Writing Gods High Atop of the Thing. Seriously. That's some bad writing juju you've just brought down on your poor manuscript. Here's why.
The ONLY way that this file can EVER be called "FINAL" is if no-one ever reads it again or contracts it for publication. In other words, the only way this particular document is "FINAL" is if it's DEAD.
In fact, if your manuscript is both lucky and good enough to get contracted somewhere, it is highly unlikely that you will ever be in possession of the final document file. There will be plenty of edits, back and forth, between you and your editor. She'll tell you to do things, and you'll do them. Great. But you won't be finished there. She'll give you more edits. And you'll do them too. Then it will go to copyedit and a copyeditor will probably send back more edits for you to deal with. You'll approve some, make a few more changes. And then the file will go to design. From here on in, the "file" is out of your hands.
And guess what? It's STILL not "final." A proofer will find more changes. There may be some layout issues - these are changes that you won't really have anything say in. If the work is a picture book, there may be a whole new set of issues that come up once the text and the pictures are joined together for the first time. The flow might need adjusting once the pages are laid out. Any number of things could still change at this point.
Even once everyone is pretty well satisfied with the way things look, there will be galley proofs that come back from the printers. Things could still change. Heck, you could decide that the character's dress really OUGHT to have been purple in the last chapter. (Your publisher will probably throw a fit, but you could still make that change.) Even so, you will NOT be in possession of the final document. The printers will. Right up until the last print button has been pushed, the document is not final.